diff options
Diffstat (limited to 'src/openvpn/crypto_openssl.c')
| -rw-r--r-- | src/openvpn/crypto_openssl.c | 753 |
1 files changed, 753 insertions, 0 deletions
diff --git a/src/openvpn/crypto_openssl.c b/src/openvpn/crypto_openssl.c new file mode 100644 index 0000000..5342502 --- /dev/null +++ b/src/openvpn/crypto_openssl.c @@ -0,0 +1,753 @@ +/* + * OpenVPN -- An application to securely tunnel IP networks + * over a single TCP/UDP port, with support for SSL/TLS-based + * session authentication and key exchange, + * packet encryption, packet authentication, and + * packet compression. + * + * Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net> + * Copyright (C) 2010 Fox Crypto B.V. <openvpn@fox-it.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program (see the file COPYING included with this + * distribution); if not, write to the Free Software Foundation, Inc., + * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +/** + * @file Data Channel Cryptography OpenSSL-specific backend interface + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#elif defined(_MSC_VER) +#include "config-msvc.h" +#endif + +#include "syshead.h" + +#if defined(ENABLE_CRYPTO) && defined(ENABLE_CRYPTO_OPENSSL) + +#include "basic.h" +#include "buffer.h" +#include "integer.h" +#include "crypto_backend.h" +#include <openssl/objects.h> +#include <openssl/evp.h> +#include <openssl/des.h> + +/* + * Check for key size creepage. + */ + +#if MAX_CIPHER_KEY_LENGTH < EVP_MAX_KEY_LENGTH +#warning Some OpenSSL EVP ciphers now support key lengths greater than MAX_CIPHER_KEY_LENGTH -- consider increasing MAX_CIPHER_KEY_LENGTH +#endif + +#if MAX_HMAC_KEY_LENGTH < EVP_MAX_MD_SIZE +#warning Some OpenSSL HMAC message digests now support key lengths greater than MAX_HMAC_KEY_LENGTH -- consider increasing MAX_HMAC_KEY_LENGTH +#endif + +/* + * + * Workarounds for incompatibilites between OpenSSL libraries. + * Right now we accept OpenSSL libraries from 0.9.5 to 0.9.7. + * + */ + +#if SSLEAY_VERSION_NUMBER < 0x00907000L + +/* Workaround: EVP_CIPHER_mode is defined wrong in OpenSSL 0.9.6 but is fixed in 0.9.7 */ +#undef EVP_CIPHER_mode +#define EVP_CIPHER_mode(e) (((e)->flags) & EVP_CIPH_MODE) + +#define DES_cblock des_cblock +#define DES_is_weak_key des_is_weak_key +#define DES_check_key_parity des_check_key_parity +#define DES_set_odd_parity des_set_odd_parity + +#define HMAC_CTX_init(ctx) CLEAR (*ctx) +#define HMAC_Init_ex(ctx,sec,len,md,impl) HMAC_Init(ctx, sec, len, md) +#define HMAC_CTX_cleanup(ctx) HMAC_cleanup(ctx) +#define EVP_MD_CTX_cleanup(md) CLEAR (*md) + +#define INFO_CALLBACK_SSL_CONST + +#endif + +static inline int +EVP_CipherInit_ov (EVP_CIPHER_CTX *ctx, const EVP_CIPHER *type, uint8_t *key, uint8_t *iv, int enc) +{ + return EVP_CipherInit (ctx, type, key, iv, enc); +} + +static inline int +EVP_CipherUpdate_ov (EVP_CIPHER_CTX *ctx, uint8_t *out, int *outl, uint8_t *in, int inl) +{ + return EVP_CipherUpdate (ctx, out, outl, in, inl); +} + +static inline bool +cipher_ok (const char* name) +{ + return true; +} + +#ifndef EVP_CIPHER_name +#define EVP_CIPHER_name(e) OBJ_nid2sn(EVP_CIPHER_nid(e)) +#endif + +#ifndef EVP_MD_name +#define EVP_MD_name(e) OBJ_nid2sn(EVP_MD_type(e)) +#endif + +#if HAVE_OPENSSL_ENGINE +#include <openssl/engine.h> + +static bool engine_initialized = false; /* GLOBAL */ + +static ENGINE *engine_persist = NULL; /* GLOBAL */ + +/* Try to load an engine in a shareable library */ +static ENGINE * +try_load_engine (const char *engine) +{ + ENGINE *e = ENGINE_by_id ("dynamic"); + if (e) + { + if (!ENGINE_ctrl_cmd_string (e, "SO_PATH", engine, 0) + || !ENGINE_ctrl_cmd_string (e, "LOAD", NULL, 0)) + { + ENGINE_free (e); + e = NULL; + } + } + return e; +} + +static ENGINE * +setup_engine (const char *engine) +{ + ENGINE *e = NULL; + + ENGINE_load_builtin_engines (); + + if (engine) + { + if (strcmp (engine, "auto") == 0) + { + msg (M_INFO, "Initializing OpenSSL auto engine support"); + ENGINE_register_all_complete (); + return NULL; + } + if ((e = ENGINE_by_id (engine)) == NULL + && (e = try_load_engine (engine)) == NULL) + { + msg (M_FATAL, "OpenSSL error: cannot load engine '%s'", engine); + } + + if (!ENGINE_set_default (e, ENGINE_METHOD_ALL)) + { + msg (M_FATAL, "OpenSSL error: ENGINE_set_default failed on engine '%s'", + engine); + } + + msg (M_INFO, "Initializing OpenSSL support for engine '%s'", + ENGINE_get_id (e)); + } + return e; +} + +#endif /* HAVE_OPENSSL_ENGINE */ + +void +crypto_init_lib_engine (const char *engine_name) +{ +#if HAVE_OPENSSL_ENGINE + if (!engine_initialized) + { + ASSERT (engine_name); + ASSERT (!engine_persist); + engine_persist = setup_engine (engine_name); + engine_initialized = true; + } +#else + msg (M_WARN, "Note: OpenSSL hardware crypto engine functionality is not available"); +#endif +} + +/* + * + * Functions related to the core crypto library + * + */ + +void +crypto_init_lib (void) +{ +#ifndef USE_SSL +#ifndef ENABLE_SMALL + ERR_load_crypto_strings (); +#endif + OpenSSL_add_all_algorithms (); +#endif + + /* + * If you build the OpenSSL library and OpenVPN with + * CRYPTO_MDEBUG, you will get a listing of OpenSSL + * memory leaks on program termination. + */ + +#ifdef CRYPTO_MDEBUG + CRYPTO_mem_ctrl(CRYPTO_MEM_CHECK_ON); +#endif +} + +void +crypto_uninit_lib (void) +{ +#ifndef USE_SSL + EVP_cleanup (); +#ifndef ENABLE_SMALL + ERR_free_strings (); +#endif +#endif + +#ifdef CRYPTO_MDEBUG + FILE* fp = fopen ("sdlog", "w"); + ASSERT (fp); + CRYPTO_mem_leaks_fp (fp); + fclose (fp); +#endif + +#if HAVE_OPENSSL_ENGINE + if (engine_initialized) + { + ENGINE_cleanup (); + engine_persist = NULL; + engine_initialized = false; + } +#endif +} + +void +crypto_clear_error (void) +{ + ERR_clear_error (); +} + +/* + * + * OpenSSL memory debugging. If dmalloc debugging is enabled, tell + * OpenSSL to use our private malloc/realloc/free functions so that + * we can dispatch them to dmalloc. + * + */ + +#ifdef DMALLOC +static void * +crypto_malloc (size_t size, const char *file, int line) +{ + return dmalloc_malloc(file, line, size, DMALLOC_FUNC_MALLOC, 0, 0); +} + +static void * +crypto_realloc (void *ptr, size_t size, const char *file, int line) +{ + return dmalloc_realloc(file, line, ptr, size, DMALLOC_FUNC_REALLOC, 0); +} + +static void +crypto_free (void *ptr) +{ + dmalloc_free (__FILE__, __LINE__, ptr, DMALLOC_FUNC_FREE); +} + +void +crypto_init_dmalloc (void) +{ + CRYPTO_set_mem_ex_functions (crypto_malloc, + crypto_realloc, + crypto_free); +} +#endif /* DMALLOC */ + +void +show_available_ciphers () +{ + int nid; + +#ifndef ENABLE_SMALL + printf ("The following ciphers and cipher modes are available\n" + "for use with " PACKAGE_NAME ". Each cipher shown below may be\n" + "used as a parameter to the --cipher option. The default\n" + "key size is shown as well as whether or not it can be\n" + "changed with the --keysize directive. Using a CBC mode\n" + "is recommended.\n\n"); +#endif + + for (nid = 0; nid < 10000; ++nid) /* is there a better way to get the size of the nid list? */ + { + const EVP_CIPHER *cipher = EVP_get_cipherbynid (nid); + if (cipher && cipher_ok (OBJ_nid2sn (nid))) + { + const unsigned int mode = EVP_CIPHER_mode (cipher); + if (mode == EVP_CIPH_CBC_MODE +#ifdef ALLOW_NON_CBC_CIPHERS + || mode == EVP_CIPH_CFB_MODE || mode == EVP_CIPH_OFB_MODE +#endif + ) + printf ("%s %d bit default key (%s)\n", + OBJ_nid2sn (nid), + EVP_CIPHER_key_length (cipher) * 8, + ((EVP_CIPHER_flags (cipher) & EVP_CIPH_VARIABLE_LENGTH) ? + "variable" : "fixed")); + } + } + printf ("\n"); +} + +void +show_available_digests () +{ + int nid; + +#ifndef ENABLE_SMALL + printf ("The following message digests are available for use with\n" + PACKAGE_NAME ". A message digest is used in conjunction with\n" + "the HMAC function, to authenticate received packets.\n" + "You can specify a message digest as parameter to\n" + "the --auth option.\n\n"); +#endif + + for (nid = 0; nid < 10000; ++nid) + { + const EVP_MD *digest = EVP_get_digestbynid (nid); + if (digest) + { + printf ("%s %d bit digest size\n", + OBJ_nid2sn (nid), EVP_MD_size (digest) * 8); + } + } + printf ("\n"); +} + +void +show_available_engines () +{ +#if HAVE_OPENSSL_ENGINE /* Only defined for OpenSSL */ + ENGINE *e; + + printf ("OpenSSL Crypto Engines\n\n"); + + ENGINE_load_builtin_engines (); + + e = ENGINE_get_first (); + while (e) + { + printf ("%s [%s]\n", + ENGINE_get_name (e), + ENGINE_get_id (e)); + e = ENGINE_get_next (e); + } + ENGINE_cleanup (); +#else + printf ("Sorry, OpenSSL hardware crypto engine functionality is not available.\n"); +#endif +} + +/* + * + * Random number functions, used in cases where we want + * reasonably strong cryptographic random number generation + * without depleting our entropy pool. Used for random + * IV values and a number of other miscellaneous tasks. + * + */ + +int rand_bytes(uint8_t *output, int len) +{ + return RAND_bytes (output, len); +} + +/* + * + * Key functions, allow manipulation of keys. + * + */ + + +int +key_des_num_cblocks (const EVP_CIPHER *kt) +{ + int ret = 0; + const char *name = OBJ_nid2sn (EVP_CIPHER_nid (kt)); + if (name) + { + if (!strncmp (name, "DES-", 4)) + { + ret = EVP_CIPHER_key_length (kt) / sizeof (DES_cblock); + } + else if (!strncmp (name, "DESX-", 5)) + { + ret = 1; + } + } + dmsg (D_CRYPTO_DEBUG, "CRYPTO INFO: n_DES_cblocks=%d", ret); + return ret; +} + +bool +key_des_check (uint8_t *key, int key_len, int ndc) +{ + int i; + struct buffer b; + + buf_set_read (&b, key, key_len); + + for (i = 0; i < ndc; ++i) + { + DES_cblock *dc = (DES_cblock*) buf_read_alloc (&b, sizeof (DES_cblock)); + if (!dc) + { + msg (D_CRYPT_ERRORS, "CRYPTO INFO: check_key_DES: insufficient key material"); + goto err; + } + if (DES_is_weak_key(dc)) + { + msg (D_CRYPT_ERRORS, "CRYPTO INFO: check_key_DES: weak key detected"); + goto err; + } + if (!DES_check_key_parity (dc)) + { + msg (D_CRYPT_ERRORS, "CRYPTO INFO: check_key_DES: bad parity detected"); + goto err; + } + } + return true; + + err: + ERR_clear_error (); + return false; +} + +void +key_des_fixup (uint8_t *key, int key_len, int ndc) +{ + int i; + struct buffer b; + + buf_set_read (&b, key, key_len); + for (i = 0; i < ndc; ++i) + { + DES_cblock *dc = (DES_cblock*) buf_read_alloc(&b, sizeof(DES_cblock)); + if (!dc) + { + msg (D_CRYPT_ERRORS, "CRYPTO INFO: fixup_key_DES: insufficient key material"); + ERR_clear_error (); + return; + } + DES_set_odd_parity (dc); + } +} + + +/* + * + * Generic cipher key type functions + * + */ + + +const EVP_CIPHER * +cipher_kt_get (const char *ciphername) +{ + const EVP_CIPHER *cipher = NULL; + + ASSERT (ciphername); + + cipher = EVP_get_cipherbyname (ciphername); + + if ((NULL == cipher) || !cipher_ok (OBJ_nid2sn (EVP_CIPHER_nid (cipher)))) + msg (M_SSLERR, "Cipher algorithm '%s' not found", ciphername); + + if (EVP_CIPHER_key_length (cipher) > MAX_CIPHER_KEY_LENGTH) + msg (M_FATAL, "Cipher algorithm '%s' uses a default key size (%d bytes) which is larger than " PACKAGE_NAME "'s current maximum key size (%d bytes)", + ciphername, + EVP_CIPHER_key_length (cipher), + MAX_CIPHER_KEY_LENGTH); + + return cipher; +} + +const char * +cipher_kt_name (const EVP_CIPHER *cipher_kt) +{ + if (NULL == cipher_kt) + return "[null-cipher]"; + return EVP_CIPHER_name (cipher_kt); +} + +int +cipher_kt_key_size (const EVP_CIPHER *cipher_kt) +{ + return EVP_CIPHER_key_length (cipher_kt); +} + +int +cipher_kt_iv_size (const EVP_CIPHER *cipher_kt) +{ + return EVP_CIPHER_iv_length (cipher_kt); +} + +int +cipher_kt_block_size (const EVP_CIPHER *cipher_kt) +{ + return EVP_CIPHER_block_size (cipher_kt); +} + +int +cipher_kt_mode (const EVP_CIPHER *cipher_kt) +{ + ASSERT(NULL != cipher_kt); + return EVP_CIPHER_mode (cipher_kt); +} + +/* + * + * Generic cipher context functions + * + */ + + +void +cipher_ctx_init (EVP_CIPHER_CTX *ctx, uint8_t *key, int key_len, + const EVP_CIPHER *kt, int enc) +{ + ASSERT(NULL != kt && NULL != ctx); + + CLEAR (*ctx); + + EVP_CIPHER_CTX_init (ctx); + if (!EVP_CipherInit_ov (ctx, kt, NULL, NULL, enc)) + msg (M_SSLERR, "EVP cipher init #1"); +#ifdef HAVE_EVP_CIPHER_CTX_SET_KEY_LENGTH + if (!EVP_CIPHER_CTX_set_key_length (ctx, key_len)) + msg (M_SSLERR, "EVP set key size"); +#endif + if (!EVP_CipherInit_ov (ctx, NULL, key, NULL, enc)) + msg (M_SSLERR, "EVP cipher init #2"); + + /* make sure we used a big enough key */ + ASSERT (EVP_CIPHER_CTX_key_length (ctx) <= key_len); +} + +void +cipher_ctx_cleanup (EVP_CIPHER_CTX *ctx) +{ + EVP_CIPHER_CTX_cleanup (ctx); +} + +int +cipher_ctx_iv_length (const EVP_CIPHER_CTX *ctx) +{ + return EVP_CIPHER_CTX_iv_length (ctx); +} + +int +cipher_ctx_block_size(const EVP_CIPHER_CTX *ctx) +{ + return EVP_CIPHER_CTX_block_size (ctx); +} + +int +cipher_ctx_mode (const EVP_CIPHER_CTX *ctx) +{ + return EVP_CIPHER_CTX_mode (ctx); +} + +int +cipher_ctx_reset (EVP_CIPHER_CTX *ctx, uint8_t *iv_buf) +{ + return EVP_CipherInit_ov (ctx, NULL, NULL, iv_buf, -1); +} + +int +cipher_ctx_update (EVP_CIPHER_CTX *ctx, uint8_t *dst, int *dst_len, + uint8_t *src, int src_len) +{ + return EVP_CipherUpdate_ov (ctx, dst, dst_len, src, src_len); +} + +int +cipher_ctx_final (EVP_CIPHER_CTX *ctx, uint8_t *dst, int *dst_len) +{ + return EVP_CipherFinal (ctx, dst, dst_len); +} + + +void +cipher_des_encrypt_ecb (const unsigned char key[DES_KEY_LENGTH], + unsigned char *src, + unsigned char *dst) +{ + DES_key_schedule sched; + + DES_set_key_unchecked((DES_cblock*)key, &sched); + DES_ecb_encrypt((DES_cblock *)src, (DES_cblock *)dst, &sched, DES_ENCRYPT); +} + +/* + * + * Generic message digest information functions + * + */ + + +const EVP_MD * +md_kt_get (const char *digest) +{ + const EVP_MD *md = NULL; + ASSERT (digest); + md = EVP_get_digestbyname (digest); + if (!md) + msg (M_SSLERR, "Message hash algorithm '%s' not found", digest); + if (EVP_MD_size (md) > MAX_HMAC_KEY_LENGTH) + msg (M_FATAL, "Message hash algorithm '%s' uses a default hash size (%d bytes) which is larger than " PACKAGE_NAME "'s current maximum hash size (%d bytes)", + digest, + EVP_MD_size (md), + MAX_HMAC_KEY_LENGTH); + return md; +} + +const char * +md_kt_name (const EVP_MD *kt) +{ + if (NULL == kt) + return "[null-digest]"; + return EVP_MD_name (kt); +} + +int +md_kt_size (const EVP_MD *kt) +{ + return EVP_MD_size(kt); +} + + +/* + * + * Generic message digest functions + * + */ + +int +md_full (const EVP_MD *kt, const uint8_t *src, int src_len, uint8_t *dst) +{ + unsigned int in_md_len = 0; + + return EVP_Digest(src, src_len, dst, &in_md_len, kt, NULL); +} + +void +md_ctx_init (EVP_MD_CTX *ctx, const EVP_MD *kt) +{ + ASSERT(NULL != ctx && NULL != kt); + + CLEAR (*ctx); + + EVP_MD_CTX_init (ctx); + EVP_DigestInit(ctx, kt); +} + +void +md_ctx_cleanup(EVP_MD_CTX *ctx) +{ + EVP_MD_CTX_cleanup(ctx); +} + +int +md_ctx_size (const EVP_MD_CTX *ctx) +{ + return EVP_MD_CTX_size(ctx); +} + +void +md_ctx_update (EVP_MD_CTX *ctx, const uint8_t *src, int src_len) +{ + EVP_DigestUpdate(ctx, src, src_len); +} + +void +md_ctx_final (EVP_MD_CTX *ctx, uint8_t *dst) +{ + unsigned int in_md_len = 0; + + EVP_DigestFinal(ctx, dst, &in_md_len); +} + + +/* + * + * Generic HMAC functions + * + */ + + +void +hmac_ctx_init (HMAC_CTX *ctx, const uint8_t *key, int key_len, + const EVP_MD *kt) +{ + ASSERT(NULL != kt && NULL != ctx); + + CLEAR(*ctx); + + HMAC_CTX_init (ctx); + HMAC_Init_ex (ctx, key, key_len, kt, NULL); + + /* make sure we used a big enough key */ + ASSERT (HMAC_size (ctx) <= key_len); +} + +void +hmac_ctx_cleanup(HMAC_CTX *ctx) +{ + HMAC_CTX_cleanup (ctx); +} + +int +hmac_ctx_size (const HMAC_CTX *ctx) +{ + return HMAC_size (ctx); +} + +void +hmac_ctx_reset (HMAC_CTX *ctx) +{ + HMAC_Init_ex (ctx, NULL, 0, NULL, NULL); +} + +void +hmac_ctx_update (HMAC_CTX *ctx, const uint8_t *src, int src_len) +{ + HMAC_Update (ctx, src, src_len); +} + +void +hmac_ctx_final (HMAC_CTX *ctx, uint8_t *dst) +{ + unsigned int in_hmac_len = 0; + + HMAC_Final (ctx, dst, &in_hmac_len); +} + +#endif /* ENABLE_CRYPTO && ENABLE_CRYPTO_OPENSSL */ |